Spline count on a 240D Bosch PES4 MW pump shaft snout is 67 teeth...

Would be 68 teeth if the missing tooth was in the empty index slot...

__________________
1978 Yellow 300D (The Mustard Toad)
1980 Blue 240D (The Iron Toad)
1989 Grey Mitsu.4WD Mighty Max Pickup (Needs a Diesel transplant bad)

(Open the pod bay doors HAL)

Michael,
Remember that the IP turns 360 for every 720 of crankshaft rotation on these diesels... just as the distributor does in relation to the crank on ALL GAS 4-cycle engines. I didn't remember exactly how many teeth Yellit counted so I went back to our 2007 emails on this subject and see that he counted either 67 or 68 and this equates to ~5.3 degrees of IP shaft rotation OR ~10.6 degrees of crank rotation per tooth! We then measured the radius out to the mounting bolt positions and calculated how much timing the slot length in the flange reprents in timing degrees and that is how we came up with the limit of ~9 degrees of timing change... about the same as 1tooth...
that is unless you slip the splined shaft coupling by 1 or more teeth!

I'll try to dig up my source info and send it to you OFF-forum!

Your experience with resetting the splined drive coupling of these IP(s) is testament as to just how easily many DIYers and experienced Mechanics alike might make this coupling such that the engine canNOT be adjusted to "spec" without resetting the coupling by 1 or 2 teeth!

Oops... wouldn't you know it, I should have read through all of the new POSTs before I shot my mouth off... I see now that "Yellet" [Kevin] has clarified the tooth count!
Regards,

Glad to see that everyone hadn't died or got their fingers all ripped off from misapplication of one sort of method or another. Seems that an awful lot of jawboning had been done about a very simple thing. Good gravy, it can't be that difficult to put a millivoltmeter on and see what happens. How bad of a job could we do on this when the IP can't be moved very far and the engine still not be too far out of whack. Maybe it would be good to do a drip adjustment to bring it up close and then the mvm to refine it further. It would be obvious that the fine tune would not require but a small adjustment that would not be so far out that it would be detrimental to the engine.

I like the possibility of being able to identify the odd cylinder and see what could be the problem and maybe adjust it to the rest for balance. Requires no disassembly. Very little time. The pretender/wrencher gets to think that they really did something. Impresses the hell out of the significant other.

The problem comes in when one does not remain aware of the principles involved and gets too far outside of the box. This may not be for every owner. Not every driver or elementary wrencher may be hip enough for this tricky bit of fiddling and would be better served by letting someone with a bit more permagrease under their fingernails step in.

However, "nothing ventured, nothing ruined", I always say. And nobody ever got anywhere without busting something. "If it ain't broke--you ain't trying"--Red Green

Git 'er done. Thanks for the ideas. I got a bunch of iron to use em on.

Sparky

Diagnostics is fine and probably a decent way to pinpoint a stubborn running problem. Using it to tune the engine by setting base timing or "adjusting" the plunger barrel rotation is not a good choice.

Curious about using good EGT probes on each cyl. exhaust manifold port as cylinder performance indicators....easier to swap around than glow plugs and more accurate with better resolution on the readings....
Lots of aircraft type on ebay often....just have to do some tap & drill fun to get them in....
Glow plugs have a lot of variables that introduce unknowns as test tools...and they change at different rates as they age....that is my worry....
Would be interesting to see how glow plug millivolt levels track EGT readings on the same engine.....this may be my next experiment for more info....

Thats a good one...(Nothing ventured...Nothing ruined)...!!!

__________________
1978 Yellow 300D (The Mustard Toad)
1980 Blue 240D (The Iron Toad)
1989 Grey Mitsu.4WD Mighty Max Pickup (Needs a Diesel transplant bad)

(Open the pod bay doors HAL)

I could not ask this question and not show my ignorance... but what the hey:

What is " EGT " ?

Sounds like specialized test probes mounted at each exhaust port on an engine in order to analize temperature or exhaust gases?

Are they placed internal or external?

Is this using "UV" temperature sensing technology?

Regards,

EGT---exhaust gas temperature. Important to know in high output diesel and jet turbine engines since, at least, in diesels, one can boost too far and burn more fuel at higher pressures creating higher temperature internally and exposing parts to higher stresses than designed for.
Then things go bad at a time of critical operating conditions creating disapointment all around. You can feed fuel and air to a combustion chamber only so much and the machinery has no particular concern but to eat it up and produce power until it blows-------kinda like some fat people we have seen on Monty Python.

In my jet driving days, the EGT gauge was a part of the important engine monitoring set we kept track of in full-power operation lest we get that sudden "let down feeling".

Odd EGT readings from different cylinders would indicate trouble in the very high or very low cylinder and a look-see would be indicated. A piezo electric sensor designed for the purpose would be much more reliable and predictable as a temperature indicator than the use of the glow plug that is only incidentally able to produce a voltage upon heating, it's purpose, of course, to be the ignitor for the fuel/air mix in the pressurized chamber of the internal combustion cylinder.

What we are looking for is simply to find that specific moment relative to TDC which is most productive of power, and/or economy, to inject the measured portion of diesel fuel into the compressed, and heated air in the cylinder without creating higher temps than the engine can sustain without damage.

It is understood that the specific timing must change as frequency of combustion cycles increases with RPM because the flame-spread/speed-of-burn stays constant for a specific mixture under a consistant pressure while time-related intervals of pressure build gets shorter with RPM increase. The faster the engine turns, the earlier the combustion needs to initiate so that peak pressure is produced in the combustion chamber at the most opportune moment to drive the piston down. Too early and it wants to drive the piston back down as it is rising. Too late and it wastes the available pressure generated by the explosion. It is simply a matter of finding out what is going on in the cylinders in order to prescribe the most optimal injection timing for the most efficient production of power.

We can still use the glow plugs if we remain aware of the deficiencies of the unstable readings obtained and accomodate that variation as we determine the cause/effect of the timing as it relates to power production without inducing deleterious effects on the mechanical parts. (mouthful)

I would suggest that only those who are willing to educate themselves re the technical aspects of this subject and, also, who are willing to risk their "ride" to their own manipulations, to try this stuff----- lest the "ride" becomes the "couch".

Enough of this posturing.

So, ----use it, but with very studied awareness of the limitations. And, backup your findings with other observations by reliable, proven methods before buzzing off into the wild blue yonder. Best wishes.

Sparky

One of the SVO users at infopop.. a few years ago... began using this method to also evaluate the combustion quality on the fly. He had MV readings feed into a laptop while driving.

how does it work? simple..... add electricity to metal you get heat.

Electricity+metal = heat.

Simple math says reverse this.

Heat+metal=Electricity.

so the more your getting a full complete burn from combustion in an area near a glow plug the heat produced will cause an electrical charge in the glow plug. The higher the electrical charge the more heat (better combustion) is being produced.

Of course that assumes the GP is not in activation mode duhhhh.. :p

Unfortunately many diesels no longer have GP's to take measures off of.

You might use google advance and search the biodieselinfopop website. A good key word to search for escapes me right now

__________________
"Know other lessons I need to learn? TELL me. Tired of learning'em the hard way".

Glow Plug Wait: [i} Time of silence in homage Rudolph Diesel. Longer you own a diesel. more honor you give". [/i]

Life; SNAFU Situation Normal All Fouled Up, & FUBAR: Fouled Up Beyond All Repair

-Now: Snafued Jeep TJ w/OM617 2Be daily driver & building SS M1079 w/Ambo boxed /live in Adv. Truck, Diesel KLR conversion
-Sold 62 UNIMOG Camper w/617 Turbo, 85 300SD

" gs sparhawk "... Sparky,
Your POST above has me wondering IF YOU or anyone else following this THREAD knows where I can find the timing -vs- RPM specs for these early 616 and 617 diesel engines?

The reason I ask, is that with our Kent-Moore timing light/test equipment we are able to dynamically observe the timing changes with our strobe light as we vary RPM(s) with the throttle. I would like to know what timing changes to expect from these in-line Bosch IP(s) so we will know IF it is too much out of "SPEC"!
Regards,

Mercedes shows a tool, part #617 589 07 21 00 that fastens onto the IP and the block to get the small IP movement required.
Page 07.1-114 shows the device installed and the adjustment method.

__________________
1984 300SD turbo 126
"My true love"

God made me an atheist and who am I to question His wisdom

Unable to see the pics and drawings in this thread. Is that a setting or ....?

__________________
1984 300SD turbo 126
"My true love"

God made me an atheist and who am I to question His wisdom

Here is the rig I used to rotate the IP on my 240D.
The round notch fits around the #1 element fitting with a little clearance.
The left and right bolts tighten the rig to the square front end. The fixed bolt on top is for a long wrench to act as a push bar. If anyone can use this tool it is yours for the cost of shipping.
My IP rig for my 300D is on loan. When I get it back I will post a pic. It looks much this one but thinner to clear the oil dip stick. No nut on top, instead a 1" x 3" pipe welded on top. Stick in the jack handle and push. The rig is held in place by a 3/8" set screw on the inboard side instead of the 2 bolts as on the 240D tool.. The outboard side of the channel has a small hook that goes under the edge of the front of the IP square by just 1/8". I tried to rig a push device against the fender wall but it was in the way to tighten the easy front nut so gave up on that Idea. The rotation to set the IP is so little the steel lines are only a small problem. After my adjustment I undid the top nuts and bent the lines to fit without any tension. I have had 3 MB cars and the pump needed a little advance on all 3 for better performance and fuel economy. I think MB sets conservative.
Have fun.

__________________
1984 300SD turbo 126
"My true love"

God made me an atheist and who am I to question His wisdom

Sam,---re your request for info on timing related to RPM: It is reasonable to assume that as the RPM increases, the injection timing will precess to an earlier setting in a direct relationship to RPM. Say, at 600 RPM, the timing is set at 24 degrees Before Top Dead Center, and at 4200 RPM the timing should hypothetically be 50 degrees BTDC. At any point in between, the timing should be advanced proportionate to the amount of increase in RPM.

If baseline (idle RPM) is 600, and 4200 is redline, the RPM range is 3600. If the recommended advance increase is a total of 26 degrees ( remember it is a hypothetical number just now) for that RPM range, then the ratio is set and for every 1000 RPM increase, there will be a 7.22 degree increase in advance. ( or, a 3.61 degree increase for every 500 RPMs). At 1600 RPM, the advance would be 31.22 degrees. See how the relationship goes? I don't know what the recommended advance is for any RPM other than idle so I can't say what the increase should be for our engines.

I thought I read a specification re the timing at higher Rs but that number slid off my plate somewhere. Someone should be able to provide it. Maybe a friendly MB service manager. ( toss him a knockwurst and a beer) Maybe somewhere in a service manual.

Anyway, this is my take on the subject and with the supposition that it is a straight-line increase, anyone should be able to do the math once the advance is known for a specific higher RPM.

In an ignition gasoline engine, the ignition timing seems to follow a "curve" and that is adjusted for optimum performance under specific conditions at different RPMs in a high performance vehicle. Varying factors of volumetric efficiency according to design of intake passages, cam profile and exhaust effectiveness, among others, determine requirements of ignition timing. I'd guess that the factory specs have taken into account the lesser and varied performance requirements of the family grocery-getter and set the "curve" accordingly.


So, it is understood that a proper timing of ignition is a significant factor in optimum efficiency and the principle is not at all lost on diesels. Go for it, Mr. Duntov. Show me up here.

Sparky

Sparky,
Thanks for your discussion on this subject... for your thoughts have me thinking that a Bosch IP shop should know what the total amount each of their pumps are designed to advance [only mechanical I must presume] between idle and max RPM(s)... and "Yellit" [Kevin] has an official Bosch shop convenient to him so maybe he can come up with the answer for his two W123 cars which are identical to my two !
Thanks again,

'Plundering around somewhere on this forum...
'Stumbled upon some of what I think are gsxr's shop notes
(Yeah, www.w124performance.com)

One of which is a treatise from Beru included in are these statements:

35
10
Combined systems
Ionic current measurement
Controlled glow systems
Glow plugs are the right starting aid to guarantee a fast
start of the diesel engine with the lowest possible strain on
the on-board network. In addition, the electrical heating
flanges that are used mainly in heavy commercial vehicles
also have potential for personal vehicle use:
 to avoid warm-up emission
 to increase smooth engine running
 to improve the load acceptance
A combination of both systems is conceivable - for a fast
start with minimal emissions and maximum smooth running
- especially with a view to the fact that the statutory
regulations on emission values are being tightened continually.
The glow plug can be used to measure the ionic current in
diesel engines due to its good position. Accordingly, it is
not necessary to introduce an additional probe into the
combustion chamber. If the heating rod of the glow plug
body is insulated and voltage is applied, an electric field
forms around the tip of the glow plug in the combustion
chamber. The charge of the particles in this field leaks out
of the electrodes. With a suitable circuit, this current can
be measured, amplified and finally transferred to the engine
control device in a treated form.
Possible areas of application:
 Identification of combustion interruption
 Equation of cylinders in terms of the start of combustion
and the balancing of tolerances in the injection and
suction system
 Satisfaction of OBD requirements through direct
feedback from the combustion chamber
 Compensation of differing fuel qualities
Electronically controlled systems will gradually replace the
self-regulating glow plugs. Intensive research is being
carried out on the development of suitable systems that do
not require any complex calculation of the control output
in dependence on the engine parameters. In the future, the
upstream engine control device will only communicate the
glow requirements to the glow control device in the form
of a target value; the glow control device then applies the
required voltage to the glow plug. Special glow plugs will
be developed for this purpose, which are able to report
back to the glow time control device a stable temperature
signal than can be analysed easily.

If y'all are already cognizant of this info,'Sorry for re-posting.

__________________
'84 300SD sold
124.128